Filter disk



FIG. 1 is a front perspective view of the filter disk particularly illustrating the porous cover connected to one side of a filter material;

FIG. 2 is a rear perspective view of the filter disk;

FIG. 3 is a front view;

FIG. 4 is a rear view; and,

FIG. 5 is a side view. 

CLAIM The ornamental design for a “filter disk,” as shown and described. 